低浓度弱碱三元复合体系与高温油藏的适应性

Adaptability of Low Concentration Weak Base ASP Displacement System for High Temperature Reservoir

李永太 鲁永辉 董 帅 孔柏岭

LI Yongtai LU Yonghui DONG Shuai KONG Bailing

为了改善特高含水高温油藏Ⅳ5-11层系水驱开发效果， 系统研究了 Na2 CO3 弱碱三元复合体系与高温油藏 的匹配关系。室内研究与现场应用结果表明， Ⅳ5-11层系油藏条件下， 弱碱三元复合体系（Na2 CO3 /表面活性剂 SH6/聚合物 ZL-II） 高温稳定性好， 在 81℃下老化 180 d后， 油水界面张力维持在 10-4 mN/m数量级， 黏度保留率为 147.6%； 该体系对地层溶蚀作用较弱、 碱耗小、 地层伤害不明显， 地面碱结垢现象不严重， Na2 CO3 具备从注入井到 油井全程作用的能力。弱碱三元复合驱技术在Ⅳ5-11 层系现场应用取得优异的增油降水效果， 峰值含水由 97.9%降至 90.2%， 日产油由 23.0 t升至 106.1 t， 阶段提高采收率 9.1个百分点， 预计最终提高采收率 14.2%。图 4 表 3参 16

In order to improve water flooding efficiency of zone Ⅳ5-11， a mature field with high temperature of 81.0℃， high water cut of 97.9% and high recovery factor of 53.3%， the adaptability of weak base（Na2CO3）ASP displacement system for high temperature reservoir was studied. The experimental results and field application results showed that the long term thermal stability of weak base ASP flooding formula was good， after ageing 180 days at 81℃， the interfacial tension（IFT）between the system and the crude oil maintained about 10-4 mN/m magnitude， and viscosity retention ratio was 147.6%. The damage of the system to the formation is not obvious with weak dissolution and low alkali consumption under Ⅳ5-11 reservoir conditions. The Na2CO3 played a great role in the whole process from the injecting well to the produced well. The weak base ASP flooding technology had been used in Ⅳ5-11 block successfully， the oil production of center produced well increased from 23.0 t/d to 106.1 t/d， water cut reduced from 97.9% to 90.2％， the oil recovery had been enhanced by 9.1% OOPI， the predicted oil recovery would be increased by 14.2% OOPI